Mixtures of an olefin copolymer of ethylene-propylene and ethylene-butene vulcanizable with an organic peroxide and of an unsaturated polyester, and elastomers obtained therefrom



3235 625 MIXTURES OF AN OLlEFIN COPOLYMER OF ETHYLENE-PROPYLENE AND ETHYLENE-BU- 3,235,625 Patented Feb. 15, 1966 ice Moreover, the unsaturated polyesters of our invention also have the capacity of exerting a lubricating action during the extrusion of the crude mixture, thus consid- TENE VULCANIZABLE WITH AN ORGANIC erab'ly improving the extrudability of the mixture. PEROXIDE AND OF AN UNSATURATED POLY- It has been found that, in order to obtain the benefits of AND ELASTOMERS OBTAINED THERE- all these effects, namely, plasticization, co-vulcanization and lubrication from a single substance this substance l i g f 3232 3 212 fififig:i fi i gzg g g giz gg rnust be in the liquid or semi-liquid state under the processnndilstria Mineraria e Chimica, Milan Italy, a corpm ing conditions of the mixture and must contain double ration of Italy bonds of the maleic type, partly esterified, along with No Drawing. Filed Apr. 20, 1962, Ser. No. 188,988 free a y g and y s r s groups Claims priority, application Italy Apr. 24, 1961, lmpart certaln P y t0 the IIIIX'EUTC- I 7,658/61 Appropriate substances which function as plasticizers, 12 Claims. (Cl. 260873) lubricants and covulcanizing agents comprise polyesters The present invention relates to the preparation of mix- Obtamed l condenstatlof} by WB'HKHOWH methods f tures of a copolymer of ethylene wit-h alpha-olefins such as Sat'UTFltBd dJCaPbOXYhC atclds 11Ch 5-, milleifl, l l rppropylene and/ or b utene, which copolymer is vulcanizable ma-leic, fumar1c, mucon1c, citraconic, mesaconic, itaconic, with an organic Peroxide and an 11nsatumtgd polyester methylenemalonic acids, etc., with compounds containing and to vulcanized elastomers obtained therefrom. two or more y y Such as hy y diethylene It is known that in those saturated elastomers which are glycol, polyoxyethylene gly l, tflmethylene glycol, 1160- vulcanizable with organic peroxides, the use of auxiliary Pentylene glycol, P py y butylelle y y" substances such as plasticizers, extenders, fillers, resins, Cerol, etc., is limited, due to the fact that such substances can The Polyester may mafle byicondenslng tWO dlfierent easily react with organic peroxides and thereby act as unsaturated dicarboxylic acids with the iiydroxyl-containul i ti i hjbit mg compound. Also, the pol ester ma contain in addi- I y y The above is particularly true as regards plasticizers. tion to the unsaturated dicarboxylic acid, a saturated di- Thus, a plasticizer, which is typically a relatively unsatucarboxylic acid. rated hydrocarbon oil or an ester, will considerably lower Th degree f polymerization f the polyesters 1 the degTe e 0f f3 111 Products Whlch are scribed above and their structure may vary Within rat-her canized with organic peroxides. wide limits, and the properties of such polyesters as plas- We h 9 3 15 g of ticizers, lubricants, and covulcanizing agents are all main present Invention t at lqul 9 yasters o tame y fi tained, provided that the polyesters are fluid at the workknown methods of condensation of unsaturated dicarin tem eratures of the mixturas Thi r H b boxylic acids with organic compounds containing two or t f d 1 t S as i a y i more esterifiable hydroxyls, exert a high plasticizing action f g yes ers w 16 ave so tenmg PomE on ethylene-alpha olefin copolymers, more particularly on Ower an 8 ethylene-propylene and ethylene-butene copolymers, and Although the combination of plasticizing, lubricating, yet when Such plasticizers are cowulcanized with S.uch and covulcanizing actions is an unusual characteristic of polymers there is no i hi i f the degree f crossthese unsaturated polyesters and is the main feature of li ki our invention, there is also another singular effect exerted TABLE I Example Number 1 2 3 4 5 6 7 8 9 10 ll 12 13 14 15 16 17 Ethylene-propylene copolynier 100 100 100 Ethylene-butene copolymer b 100 Carbon black HAF 50 Carbon black EPo 50 Silica. (Hisil) Clay (Whitetex) Polyester 5 5 Polyester Polyester Polyester L Polyester sulfhllg vzinguniantul 0.3 0.3 0.4 0.4 0.3 0.3 0.3

s r i u erox a di isopropgl b 7.1291197 p y p 1.63 2.6 1.63 1. 63 Dicumyl peroxide. 3.3 3.3 3.3 Mooney viscosity, ML (1+4), 100 0. 103 100 163 98 68 64 Tensile properties of vnlcanizates after heating at 165 C. for (minutes) 40 a0 30 40 40 40 30 30 30 40 30 30 40 30 30 30 30 Tensile strengthfl kg./cm. 189 158 173 44 200 167 169 132 85 198 154 75 181 66 74 61 Elongation at break, percent- 400 707 740 1,200 445 340 520 353 355 380 425 375 345 403 440 350 320 Modulus at 300%, kg./cm. 122 37 40 13 111 141 63 104 78 132 124 112 74 11s 53 71 60 Residual elongation at 200% 19 28 34 7 8 12 11.5 8 7.5 8 14 10 9.5 9.5 10.5 10

Ethylene-propylene copolymer containing 45 mole percent Jogo rrrgpylene and having a Mooney viscosity of 50 ML (1+4) Ethylene-butene copolymer containing 30 mole percent of ligat ng, and having a Mooney viscosity of 52 ML (1+4) "A polyester resin prepared by heating maleic anhydride (1 mole) and ethylene glycol (2 moles) at 195200 C. for 6 hours and removing water and excess glycol by vacuum distillation.

Polyester resin prepared by heating maleic anhydride (1 mole) and ethylene glycol (1 mole) at 200 C for 8 hours.

9 Polyester resin prepared by heating maleic anhydride (1 mole) and triethylene glycol (1 mole) at 200: C. for 8 hours.

1 Polyester resin prepared by heating itaconic acid (1 mole) and ethylene glycol (1 mole) at 200 'C. for 8 hours.

g Polyester resin prepared by heating maleic anhydride (1 mole) and glycerol ('1 mole) at 165 for 3 hours.

Determined on a type C specimen (ASTM D412) obtained from plates of 120 x 120 x 2 mm., with an Amsler dynamometer, with a rate of separation of the grips of 500 mm./minute.

1 Determined on specimens having a useful portion of 5 cm., kept under tension to an elongation of 200% for 1 hour and measured 1 minute after rest.

*Together with sulfur, or in substitution therefor, also qiiinonic compounds, as described in the Italian Patent 587,681 issued January 20, 1959, may be used. Preferably these compounds are selected for the group consisting of p-benzoquinone, p-quinone dioxime, 0,0-dibenzoyl-p-quinone dioxime, p-nltrosophenol in its tautomeric form, and the like.

by these polyesters on ethylene-propylene and ethylenebutene copolymers. Thus, we have surprisingly found, and this is a second feature of our invention, that the aforementioned polyesters have a considerable effectiveness in promoting the dispersion of fillers in the copolymer mixture and in promoting the interaction between filler and copolymer. This specifically results in a reinforcing of the filled vulcanizate. More particularly, mixtures of ethylene-propylene or ethylene-butene copo'lymers with siliceous fillers (clay or silica) which, as known, are hardly vulcanized with organic peroxides alone, are, in the presence of polyesters of the present invention, vulcanized to a remarkably high degree and the so vulcanized products appear to be highly reinforced.

The polyester concentration will depend on the particular type of polyester used, and generally may vary from about 0.5 to 50 parts per 100 parts of copolymer, more preferably, from about 2 to 20 parts per 100 parts of copolymer. H

The examples reported in Table I above will further illustrate our invention. All parts are by Weight unless otherwise stated.

A consideration of the foregoing data shows that the incorporation of our polyester plasticize'r does in fact improve the dispersing of the filler, whereby an improved reinforcing effect is obtained. Thus, those examples wherein an appropriate polyester is incorporated (Ex amples 6 17) show a distinctly higher modulus than the control examples (Examples 1-5) wherein no polyester is present.

Variation can be made without departing from the spirit of our invention.

Having thus described our invention what we desire to secure and hereby claim by Letters Patent is:

1. A vulcaniza'ble mixture comprising a copolymer of ethylene with an alpha-olefin selected from the group consisting of propylene and butene, an organic peroxide, and a polyester formed by condensation of at least one dicarboxylic acid containing at least one ethylenic double bond with a polyhydric alcohol,

2. The mixture of claim 1, wherein said alpha-olefin is propylene.

3. The mixture of claim 1, wherein said alpha-olefin is butene.

4. The mixture of claim 1, wherein the amount of polyester is from about 0.5 to by Weight, based on the copolymer.

5. The mixture of claim 1, wherein the dicarboxylic acid is itaconic acid.

6. The mixture of claim 1, wherein the dicarboxylic acid is maleic acid.

7. The mixture of claim 1, wherein at least two dicarboxylic acids, each having at least one ethylenic double bond, are condensed with said polyhydric alcohol.

8. The mixture of claim 1, wherein said polyester contains, in addition to an unsaturated dicarboxyl-icacid, a saturated dicarboxylic acid, said mixture containing at least one monomeric unit of unsaturated carboxylic acid per molecule of polyester.

9. The mixture of claim 1, wherein said polyester has a softening point below 180 C.

10. The mixture of claim 1, said mixture also containing a free radical acceptor selected from the group consisting of sulfur and quinonic compounds.

11. The mixture of claim 1, said mixture also containing a filler, said polyester serving as a promoter of the dispersion of said filler in the copolymer mass.

12. The shaped vulcanizate of the mixture of claim 1.

References Cited by the Examiner UNITED STATES PATENTS 2,155,590 4/1939 Garvey 260-4573 2,25 5,3 13 9/ 1941 Ellis Z872 2,426,994 9/1947 Frosch 260- 2,938,012 5/1960 Filar 260-88.2

OTHER REFERENCES Garvey et 211., Ind. & Eng. Chem, Aug. 1941, page 1062.

WILLIAM H. SHORT, Primary Examiner. 

1. A VULCANIZABLE MIXTURE COMPRISING OF COPOLYMER OF ETHYLENE WITH AN ALPHA-OLEFIN SELECTED FROM THE GROUP CONSISTING OF PROPYLENE AND BUTENE, AN ORGANIC PERIOXIDE, AND A POLYESTER FORMED BY CONDENSATION OF AT LEAST ONE DICARBOXYLIC ACID CONTAINING AT LEAST ONE ETHYLENIC DOUBLE BOND WITH A POLYHYDRIC ALCOHOL. 